Tax · free calculator
Estimated tax safe harbor calculator
Compute the minimum federal estimated tax payments to avoid the underpayment penalty — using the lesser of 90% of current year or 100/110% of prior year.
Quarterly estimated payment
Show the work
- Total required payments$32,800
- Safe harbor target$37,800
- Prior year multiplier (100% or 110%)1
The safe harbor — pay this and skip the penalty
The IRS doesn't actually care if you owe at year-end — they care if you DIDN'T pay enough in real-time. The safe harbor lets you avoid the underpayment penalty by hitting the LESSER of two thresholds:
target = MIN(
prior year tax × (1.00 or 1.10),
current year projected tax × 0.90
)The 1.00 vs 1.10 toggle: if last year's AGI was over $150k, multiplier is 1.10 (110%). Below: 1.00.
The choice — which to target
For most freelancers / business owners with growing income: target prior year × 110%. It's locked in at filing time, easy to compute, no projection error.
For folks whose income drops year-over-year: target current year × 90%. Avoids overpaying when you'd otherwise pay 110% of a high prior year.
What happens if you miss
The IRS calculates the penalty as roughly the IRS short-term rate + 3% (currently ~8%) on the shortfall, prorated by quarter. For a $5k underpayment: $400-500 penalty. Annoying but manageable.
When you can skip estimated payments entirely
- Current year owe < $1,000 (de minimis exception)
- W-2 withholding alone covers the safe harbor (most W-2 employees)
- Prior year tax = $0 (first year of filing US return)
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